Y-fronts

Y-fronts pl (plural only)

1. (plural only, British, informal) Men's or boys' briefs that have a fly as part of an inverted Y formed by the seams.
   • 1991, Stephen Fry, The Liar, London: Heinemann, →OCLC, page 9:

     Setting a spatted foot on the bench that ran down the middle of the changing-room with elegant distain, Adrian began to flip through the pile of Y-fronts and rugger shorts with his cane.

   • 2013, Mike Peyton, Mike Peyton’s Floating Assets, page 4:

     I did the latter, so in writing this I have put it on record that I am one of the few men who has spent Christmas Eve running across a Kentish marsh in his Y-fronts with two horses trotting after him in close company.

• See Thesaurus:underwear

• jocks
• bibidees
• bikini briefs